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Front. Plant Sci. | doi: 10.3389/fpls.2018.00557

Iron retention in root hemicelluloses causes genotypic variability in the tolerance to iron deficiency-induced chlorosis in maize

 Rongli Shi1,  Michael Melzer2,  Shao Jian Zheng3, Andreas Benke4, Benjamin Stich4 and  Nicolaus Von Wirén1*
  • 1Physiology & Cell Biology, Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK), Germany
  • 2Physiologie & Zellbiologie, Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK), Germany
  • 3College of Life Sciences, Zhejiang University, China
  • 4Max Planck Institut für Pflanzenzüchtungsforschung, Germany

Antagonistic interactions of phosphorus (P) hamper iron (Fe) acquisition by plants and can cause Fe deficiency-induced chlorosis. To determine physiological processes underlying adverse Fe-P interactions, the maize lines B73 and Mo17, which differ in chlorosis susceptibility, were grown hydroponically at different Fe:P ratios. In presence of P, Mo17 became more chlorotic than B73. The higher sensitivity of Mo17 to Fe deficiency was not related to Fe-P interactions in leaves but to lower Fe translocation to shoots, which coincided with a larger pool of Fe being fixed in the root apoplast of P-supplied Mo17 plants. Fractionating cell wall components from roots showed that most of the cell wall-contained P accumulated in pectin, whereas most of the Fe was bound to root hemicelluloses, revealing that co-precipitation of Fe and P in the apoplast was not responsible for Fe inactivation in roots. A negative correlation between chlorophyll index and hemicellulose-bound Fe in 85 inbred lines of B73 and Mo17 indicated that apoplastic Fe retention contributes to genotypic differences in chlorosis susceptibility of maize grown under low Fe supplies. Our study indicates that Fe retention in the hemicellulose fraction of roots is an important determinant in the tolerance to Fe deficiency-induced chlorosis of graminaceous plant species with low phytosiderophore release, like maize.

Keywords: Cell Wall, Apoplastic iron, iron-phosphorus interaction, Fe deficiency, Strategy II, nutrient interactions, nutrient efficiency

Received: 23 Feb 2018; Accepted: 09 Apr 2018.

Edited by:

GIANPIERO VIGANI, Università degli Studi di Torino, Italy

Reviewed by:

Stephane Mari, Institut National de la Recherche Agronomique (INRA), France
Rumen Ivanov, Heinrich Heine Universität Düsseldorf, Germany  

Copyright: © 2018 Shi, Melzer, Zheng, Benke, Stich and Von Wirén. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Dr. Nicolaus Von Wirén, Leibniz-Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK), Physiology & Cell Biology, Corrensstr. 3, Gatersleben, 06466, Germany,